The 18-year-old netted twice in three first-half minutes before setting up Dani Ceballos to score his first goal for the club, with Joe Willock having already added the third.
Monday night's Premier League draw against Manchester United would have been a good result for Arsenal a few years ago since Old Trafford has always been a terror for the Gunners, but the fans were very disappointed with the result and especially the performance of the team and the coach.
It's reported the former German international's relationship with Arsenal manager Unai Emery has broken down and he's looking to leave the club during the upcoming winter transfer window in order to make a fresh start.
"He needs to continue working".
The young forward warrants a starting berth and will nearly certainly have given Emery a selection headache ahead of Arsenal's game against Bournemouth on Sunday.
"For tomorrow we are thinking - it depends on the training we are going to do now - how he is feeling but if he is feeling well tomorrow he is going to play..."
Lowest Afghan Election Turnout Ever: 20%
In Kabul , turnout was sporadic and in the morning hours it was rare to see a crowded polling center. As of Sunday evening none of the candidates appeared to have raised any complaints.
"The best first 11 possible to achieve our target to win on Sunday and also adapt to that hard of playing Bournemouth".
Tierney made his debut for the Emirates side in a Carabao Cup clash against Nottingham Forest, playing a little over 70 minutes before making way for fellow full-back Hector Bellerin, who is also coming back from injury.
"He's our player now", Emery told reporters of Ozil.
"He played with the under-23s for taking confidence and he was doing actions on the pitch to feel good and to repeat them when the level is higher", Emery continued. Here are five things we learned from the 4-0 victory.
The Europa League is back this week for its usual insane slate of Thursday games, and one of the premier matchups on the schedule takes place in North London. They showed that they can perform and they can score.